It's not pinin', it's passed on!
This URL is no more!
It has ceased to be!
It's expired and gone to meet its maker!
This is a late URL!
It's a stiff!
Bereft of life, it rests in peace!
If you hadn't nailed it with your browser it would be pushing up the daisies!
Its metabolic processes are of interest only to historians!
It's hopped the net!
It's shuffled off this mortal coil!
It's run down the curtain and joined the choir invisible!
This.... is an EX-URL!